I think it's fine as 20 at least for druid's sake. Sejta, Druid tank of paragon on Lightning's blade, EU(6/7 heroic FL) heavily values stam over all other stats too. Mastery is not that great for druids tanks imo. I have 217k hp raid buffed in FL with 37% to dodge and I have been told that I am way more easier to heal than our paladin tank stacking mastery.

Comparing Earthen Vitality with Heavy savage armor kit to boot,s 30 stam w/ run speed to 44 stamina seem to be a good trade off for tanking. I think the points should be equal too. Nearly 50% extra stat is deserving of 5 pts imo =P